


My brother is so naive

by Papapaya



Category: Undertale (Video Game)
Genre: Ecto-Vagina (Undertale), Fontcest, M/M, Masturbation, Mutual Pining, Sibling Incest, i guess ill add stuff later on lmaoooooo, idk wtf to tag KJGKLSDJGDSJGLSD
Language: English
Status: In-Progress
Published: 2019-08-01
Updated: 2019-08-01
Packaged: 2020-07-28 07:23:24
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 635
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20060212
Author URL: https://archiveofourown.org/users/Papapaya/pseuds/Papapaya
Summary: Sans just can't keep his thoughts straight while rubbing one off.





	My brother is so naive

**Author's Note:**

> A really short birthday gift to myself 👌👀 please do not read this if you don't enjoy fontcest!

Papyrus was so naive. 

He could never understand these spontaneous sexual desires Sans would get every so often. He'd never get why he had to excuse himself, especially in those moments they got a little too close. A little too touchy.

So he hushed his voice and kept to himself on the bathroom floor, his back propped against the wall.

Not that it was difficult to hide these things from his sweet young brother in the first place.

Papyrus.

Was there anything that wasn't great about that guy? He took care of the house, kept them fed and even after all that, he found time to try to pull Sans out of the couch. He had dreams and goals and he never gave up on anything.

Sans shook his head after catching himself daydreaming, his lazy smile fading. He was going to rub himself off. Better stop thinking about his brother.

He sat on the floor, leaning against a wall and pushed his shorts down to his ankles, his hands traveling up his bare femurs, scraping pleasantly against the bone.

It didn’t take much for his magic to spark into existence, only a few gentle strokes to his pelvis and a soft blue lit up the room. A phalange slipped inside easily and another one followed after a few short pumps.

Curling forwards, he sank his teeth into the collar of his hoodie to muffle small groans.

None of this was really enough, he wasn’t exactly a virgin and he knew what he was missing out on. It kept nagging him in the back of his mind. 

He propped up his legs and spread them wider so he could easily reach his sweet spot. While his fingers grinded into his soft ecto flesh, his other hand came to brush over his clit which sent a whole different kind of pleasant shocks through his body.

It wasn't enough.

His desire to climax overpowered his guilt easily, it wasn't like this was the first time he allowed his fantasies to take the reins. Instead of his own thin fingers, he imagined how the coarse fabric of Papyrus' thick gloves must feel inside him. He heard his voice softly encouraging him.

When his sockets fell shut, he could even see his face, smiling down at him.

He begged his brother for more, as if he needed permission, then curled his fingers and grinded down on his sensitive little nub harder, faster. 

"Please. I'm gonna…"

He came into his hands with a single, softly moaned “Pap” and his face flushed dark blue in embarrassment. The feeling was overwhelming, building and tipping back down again in steady waves deep within him. For that blissful moment, he couldn’t even think.

When the deafening pulses of pleasure had finally died down, he pressed a palm to his forehead and sighed.

“This has to stop.”

Sans only had a short moment to wallow in his guilt before a noise from the door made him jump in shock. It was only a soft click but his nerves were always on edge in moments like these and besides, he had been so sure he locked the door.

Yanking his pants back over his pelvis, he stood on quivering legs and peeked out of the bathroom door, finding himself staring at Papyrus’ back as he was sneaking away. He was in the middle of a step when Sans spoke.

“Paps…”

Papyrus caught himself before crashing to the floor and turned to Sans hastily, a wide, overcompensating smile on his face. “Yes! Occupied! No matter, I was going to retire for the night, sleep well Sans!”

He slammed the door to his bedroom after going inside and Sans lingered there, his hand clutching the bathroom door handle, then he closed it. This time he remembered to lock.


End file.
